Color filter manufacturing method and apparatus, ink-jet device, color filter, display device, and apparatus having display device

ABSTRACT

A color filter manufacturing apparatus of this invention includes a plurality of ink-jet heads ( 120   a,    120   b,    120   c ) each having a first ink discharging nozzle group ( 108 ) in which the pitch of a plurality of ink discharging nozzles in the Y-axis direction is set to be equal to the pitch of pixels of the same color in the Y-axis direction, and a second ink discharging nozzle group having a nozzle pitch set to be equal to the pixel pitch in the Y-axis direction like the first ink discharging nozzle group. Control of an ink discharging operation is performed for only one of the first and second ink discharging nozzle groups which is to be used to color pixels of corresponding colors on a substrate ( 1 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a color filter method and apparatus formanufacturing a color filter by forming a large number of pixels coloredin a plurality of kinds of colors on a transparent substrate, an ink-jetdevice, a color filter, a display device, and an apparatus having thedisplay device.

2. Description of the Related Art

With recent advances in personal computers, especially portable personalcomputers, the demand tends to arise for liquid crystal displays,especially color liquid crystal displays. However, in order to furtherpopularize the use of liquid crystal displays, a reduction in cost mustbe achieved. Especially, it is required to reduce the cost of a colorfilter which occupies a large proportion of the total cost. Variousmethods have been tried to satisfy the required characteristics of colorfilters while meeting the above requirements. However, any methodcapable of satisfying all the requirements has not been established. Therespective methods will be described below.

The first method is a dyeing method. In the dyeing method, awater-soluble polymer material as a dyeable material is applied to aglass substrate, and the coating is patterned into a desired shape by aphotolithographic process. The obtained pattern is dipped in a dye bathto obtain a colored pattern. This process is repeated three times toform R, G, and B color filter layers.

The second method is a pigment dispersion method, which is currentlyreplacing the dyeing method. In this method, a pigment-dispersedphotosensitive resin layer is formed on a substrate and patterned into asingle-color pattern. This process is repeated three times to obtain R,G, and B color filter layers.

The third method is an electrodeposition method. In this method, atransparent electrode is patterned on a substrate, and the resultantstructure is dipped in an electrodeposition coating fluid containing apigment, a resin, an electrolyte, and the like to be colored in thefirst color by electrodeposition. This process is repeated three timesto form R, G, and B coatings. Thereafter, the resin layers are thermosetto form colored layers.

The fourth method is a print method. In this method, a pigment isdispersed in a thermosetting resin, and a print operation is performedthree times to form R, G, and B coatings separately, and thermosettingthe resins, thereby forming colored layers. In either of the abovemethods, a protective layer is generally formed on the colored layers.

The point common to these methods is that the same process must berepeated three times to obtain layers colored in three colors, i.e., R,G, and B. This causes an increase in cost. In addition, as the number ofprocesses increases, the yield decreases. In the electrodepositionmethod, limitations are imposed on pattern shapes which can be formed.For this reason, with the existing techniques, this method cannot beapplied to a TFT type color liquid display. In the print method, apattern with a fine pitch cannot be formed because of poor resolutionand poor evenness.

In order to eliminate these drawbacks, methods of manufacturing colorfilters by an ink-jet system are disclosed in Japanese Patent Laid-OpenNos. 59-75205, 63-235901, 63-294503, and 1-217320.

These references disclose, for example, a method of forming a colorfilter by an ink-jet method, in which a light-shielding film is formedon a transparent substrate to have opening portions with predeterminedregularity, and an ink is discharged from an ink-jet head onto theopening portions to color the substrate.

In general, it takes much time and cost to develop an ink-jet head. Evenif a custom ink-jet head is developed for a color filter manufacturingapparatus, since the production is smaller than that of ink-jet headsgenerally used for printers and the like, the cost of the custom ink-jethead is very high. As a result, the cost of the manufacturing apparatusbecomes high, and hence the cost of a color filter increases.

Assume that ink-jet heads generally used for printers are applied to themanufacture of color filters. The resolution of most of the existingprinter ink-jet heads is 300 dpi, 360 dpi, 400 dpi, 600 dpi, or 720 dpi.The pixel pitch of a color filter of a 9.4-inch VGA type is 300 μm(corresponding to 84.7 dpi). The pixel pitch of color filters of a10.4-inch XGA type and a 12.9-inch EWS type is 207 μm (corresponding to122.7 dpi). The pixel pitch of color filters of a 12.1-inch XGA type, a13.8-inch EWS, and a 15.5-inch EWS type is 240 μm (corresponding to105.8 dpi). There is no combination of an ink-jet head and a colorfilter whose resolution and pixel pitch match with each other or are anintegral multiple. Considering other combinations, there is hardly anycombination of an ink-jet head and a color filter whose resolution andpixel pitch match with each other or are an integral multiple.

When, therefore, an ink-jet head used for a general ink-jet printer isto be applied to a color filter manufacturing apparatus, the presentapplicant has studied a technique of matching the resolution of theink-jet head with the pixel pitch of a color filter by positioning theink-jet head obliquely with respect to a color filter substrate.

The present applicant has also studied a technique of mounting theink-jet head on the manufacturing apparatus such that the angle of theink-jet head can be changed with respect to the a color filter substrateto allow the single ink-jet head to cope with the pixel pitches ofvarious types of color filters.

When, however, the ink-jet head is mounted obliquely with respect to acolor filter, a coloring operation is performed by relatively scanningthe ink-jet head and the color filter, a relative scanning operation isrequired in excess of an amount corresponding to the oblique positioningof the ink-jet head. This increases the coloring time required for onesubstrate. Especially when an ink-jet head shorter than the effectivepixel area of a color filter is used, since a relative scanningoperation must be performed a plurality of numbers of times, a longercoloring time is required. With an increase in coloring time persubstrate, the production of color filters per unit time decreases,resulting in an increase in the cost of a color filter.

In addition, when an ink-jet head to be used is caused to stand, an inkin discharging nozzles of the ink-jet head increases its viscosity orsolidifies upon contacting air. As a result, a discharge failure, i.e.,inability to discharge the ink, or twisting, i.e., tilting of an inkdischarging direction, may occur. For this reason, the nozzle surfacesare covered with cap members when the ink-jet head is not used. Evenwith the cap members, in an initial period of a discharging operation,first some inks to be discharged from one nozzle may not be discharged,or twisting may occur because of the influence of the ink whoseviscosity has increased. If the ink is discharged onto a recordingmedium such as a paper sheet in this state, part of a character may beomitted or become excessively bright or dark, resulting in adeterioration in print quality. In order to prevent such a phenomenon, areceiving portion for receiving the pre-discharged ink is formed in acap portion or the like, and several inks are preliminarily discharged(pre-discharging operation) onto the receiving portion before an actualprinting operation is performed. This operation itself is generallyperformed in an ink-jet printer, and hence is not a special operation.

When an ink-jet head is applied to a color filter manufacturingapparatus, unlike in a general printer, a coloring operation isperformed by discharging an ink from the ink-jet head onto openingportions having predetermined regularity, as described above. Owing tothis method, the color filter manufacturing apparatus demands an inklanding accuracy 10 times higher than that in the general printer. Forthis reason, a pre-discharging operation becomes more important, and itis preferable that a pre-discharging operation always be performedbefore a color pattern is formed by discharging an ink onto a glasssubstrate.

When the manufacturing apparatus uses a long head which can color anentire glass substrate with one scanning operation after thispre-discharging operation, the following problem is not posed. When,however, the apparatus uses a short head which colors a glass substratewith a plurality of numbers of times of scanning operations, since theposition of the head relative to the substrate is changed between thescanning operations, an idling time during which the dischargingoperation of the head is stopped is required. If this time increases, adischarge failure or twisting may occur in discharging the ink in thenext scanning operation.

In coloring the entire substrate surface with a plurality of numbers oftimes of scanning operations, the same nozzles are not necessarily usedfor each scanning operation owing to the relationship between the numberof discharging nozzles which can used in one scanning operation, and thenumber of pixels constituting a color filter. For this reason, nozzleswhich have not been used in the previous scanning operation may be used.

As is apparent, since the ink in the nozzles which have not been used inthe previous scanning operation contact air without being used for along period of time as compared with the ink in the remaining nozzles,the ink in the nozzles which have not been used may increase itsviscosity or solidify. For this reason, when the ink is to be dischargedfrom the nozzles which have not been used, a discharge failure, i.e.,inability to discharge the ink, or twisting, i.e., tilting of an inkdischarging direction, may occur. As a result, a defective color filtermay be manufactured.

In order to prevent this, the head may be relatively moved to anink-receiving portion for a pre-discharging operation, which is formedin the cap portion or the like to perform a pre-discharging operationevery time a scanning operation is performed. With this operation,however, the time required to completely color one substrate increases,and the production per unit time decreases, resulting in an increase inthe cost of a color filter. That is, the present applicant found thismethod undesirable.

In addition to the above problem, the following problem is also posed.

Prior to a detailed description of this problem, the following casestudied by the present applicant will be described below with referenceto FIG. 1. In applying an ink-jet head used for a general ink-jetprinter to a color filter manufacturing apparatus, the ink-jet head ismounted obliquely with respect to a color filter substrate to match theresolution of the ink-jet head with the pixel pitch of a color filter.

FIG. 1 is a plan view showing how the pixels of a color filter arecolored by an ink-jet head. With regard to the ink-jet head, only theposition of a nozzle array is shown in FIG. 1. In this state, of apredetermined pattern, a portion to be colored in red is being colored.Note that the letters R, G, and B in the respective pixels in FIG. 1indicate that the respective pixels are to be colored in red (R), green(G), and blue (B).

Reference numeral 1013 denotes a nozzle array formed on the ink-jethead. An ink is discharged from this nozzle array to form ink dots onthe substrate. Reference numeral 1014 denotes each pixel of a colorfilter. On these pixels on the substrate, ink dots are formed.

In the case shown in FIG. 1, since the pixel pitch of the color filterdoes not coincide with the nozzle pitch of the ink-jet head, the head istilted to make the positions of every three pixels of the same color inthe Y direction coincide with the positions of the ink discharged fromevery five nozzles. Ink dots are then formed in the pixels 1014 whilethe ink-jet head is relatively moved in the X direction in FIG. 1,thereby coloring the pixels. This operation is performed using ink-jetheads for discharging red, green, and blue inks to manufacture a colorfilter. In this operation, in the ink-jet head for coloring red pixels,which is shown in FIG. 1, the second, seventh, and twelfth nozzles areused to discharge the ink, but the remaining nozzles are not used.

In this case, as this ink-jet head, a general ink-jet head having anozzle pitch of 360 dpi (70.5 μm) is used. As the color filter, a filterhaving a pixel pitch of 100 μm is used.

This ink-jet head has the following characteristics:

(1) When a nozzle clogs with a solid matter in an ink, a normaldischarging operation may not be performed. In this case, if a nozzle inuse does not properly discharge an ink, the entire ink-jet head isreplaced.

(2) In an ink-jet system using a thermal phenomenon, in particular, whena predetermined number of inks are discharged, the nozzle becomesincapable of properly discharging an ink because of scorching of the inkor the like. That is, the service life of each nozzle depends on thenumber of inks discharged. For this reason, an ink-jet head must beperiodically replaced.

(3) In the ink-jet system using the thermal phenomenon, since a heaterprovided for each nozzle which is discharging an ink generates heat,repetition of a discharging operation will raise the temperature nearthe nozzle. The amount of ink discharged depends on temperatures. Forthis reason, ink dots gradually change in size, and the ink-jet headexpands, resulting in deformation such as a change in nozzle pitch.

As described above, in a color filter manufacturing apparatus, if onlyspecific nozzles are used, the following problems are posed:

(1) When a given nozzle becomes incapable of properly discharging anink, the entire ink-jet head must be replaced, although the remainingnozzles can be used.

(2) In the ink-jet system using the thermal phenomenon, in particular,since the service life of each nozzle depends on the number of inksdischarged, head replacement must be periodically performed. In thisreplacement, the overall service life of the ink-jet head coincides withthe service life of some nozzles which have been used, although themajority of the remaining nozzles can be used.

(3) In the ink-jet system using the thermal phenomenon, in particular,as a discharging operation is performed, the temperature near eachnozzle in use rises, and the amount of ink discharged varies. For thisreason, the size and color density of ink dots formed on the substratevary, adversely affecting the uniformity of a color filter.

The following problem is also posed. An impurity may elute from acoloring material contained in an ink used for a color filter into aliquid crystal layer to cause a deterioration in display quality. Forthis reason, this ink must be purified to remove such an impurity.Consequently, the ink becomes expensive. In order to achieve a reductionin cost, a demand has arisen for a reduction in the amount of ink used.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the aboveproblems, and has as its object to provide a color filter manufacturingmethod and apparatus which can decrease the cost of an ink-jet head andthe cost of the manufacturing apparatus by using an ink-jet head used ina general printer or having a simple structure as an ink-jet head usedto manufacture a color filter.

It is another object of the present invention to provide an inexpensivecolor filter by reducing the amounts of inks used per color filter, adisplay device using the color filter, and an apparatus using thedisplay device.

It is still another object of the present invention to provide a colorfilter manufacturing method and apparatus which can stabilize thedischarging operation of an ink-jet head to suppress the occurrence ofdefective products and can shorten the drawing time required for oneglass substrate and increase the production per unit time to produce acolor filter at a lower cost when one glass substrate is to be coloredby performing a scanning operation a plurality of numbers of times, acolor filter, a display device, and an apparatus having the displaydevice.

It is still another object of the present invention to provide a colorfilter manufacturing apparatus which can shorten the idle time betweenscanning operations during which each ink discharging nozzle of anink-jet head having ink discharging nozzles arranged at a pitch equal toa pixel pitch discharges no ink, stabilize the discharging operation ofthe ink-jet head, suppress the occurrence of defective products, andincrease the yield when a drawing operation is to be performed for onesubstrate by relatively scanning the ink-jet head a plurality of numbersof times.

It is still another object of the present invention to switch acurrently used nozzle to another nozzle of the same ink-jet head.

It is still another object of the present invention to reduce thefrequency at which ink-jet heads are replaced owing to the service lifeof each nozzle.

It is still another object of the present invention to keep the size andcolor density of each ink dot constant.

In order to solve the above problems and achieve the above objects, acolor filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its firstaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging many pixels colored in the samecolor on a substrate in an X-axis direction as one direction, andperiodically forming and arranging pixels such that pixels adjacent toeach other in a Y-axis direction perpendicular to the X-axis directionare colored in different colors, comprising a plurality of ink-jet headsfor different colors, each having a plurality of ink discharging nozzlesarranged in the Y-axis direction, each ink-jet head having a first inkdischarging nozzle group, in which a pitch of the plurality of inkdischarging nozzles in the Y-axis direction is set to be equal to apitch of the pixels of the same color in the Y-axis direction, and asecond ink discharging nozzle group having a nozzle pitch set to beequal to the pixel pitch in the Y-axis direction like the first inkdischarging nozzle group, moving means for moving the relative positionsof the plurality of ink-jet heads and the substrate, and control meansfor controlling an operation of the moving means and ink dischargingoperations of the plurality of ink-jet heads, wherein when the first inkdischarging nozzle group is used to color the pixels, the second inkdischarging nozzle group is not used to color the pixels, and thecontrol means controls an ink discharging operation of only a nozzlegroup, of the first and second ink discharging nozzles, which is to beused to color pixels of corresponding colors on the substrate.

A color filter manufacturing method of the present invention ischaracterized by the following process according to its first aspect.

There is provided a manufacturing method for a color filter manufacturedby forming and arranging many pixels colored in the same color on asubstrate in an X-axis direction as one direction, and periodicallyforming and arranging pixels such that pixels adjacent to each other ina Y-axis direction perpendicular to the X-axis direction are colored indifferent colors, comprising the steps of using a plurality of ink-jetheads for different colors, each having a plurality of ink dischargingnozzles arranged in the Y-axis direction, each ink-jet head having afirst ink discharging nozzle group, in which a pitch of the plurality ofink discharging nozzles in the Y-axis direction is set to be equal to apitch of the pixels of the same color in the Y-axis direction, and asecond ink discharging nozzle group having a nozzle pitch set to beequal to the pixel pitch in the Y-axis direction like the first inkdischarging nozzle group, moving means for moving the relative positionsof the plurality of ink-jet heads and the substrate, and control meansfor controlling an operation of the moving means and ink dischargingoperations of the plurality of ink-jet heads, the second ink dischargingnozzle group for coloring of the pixels being not used when the firstink discharging nozzle group is used to color the pixels, and thecontrol means controlling an ink discharging operation of only a nozzlegroup, of the first and second ink discharging nozzles, which is to beused to color pixels of corresponding colors on the transparentsubstrate, and causing each of the ink-jet heads to discharge an inkwhile scanning the ink-jet head in the X-axis direction, and coloringall the pixels by scanning the ink-jet head once or a plurality ofnumbers of times in the X-axis direction.

A color filter of the present invention is characterized by thefollowing arrangement according to its first aspect.

There is provided a color filter manufactured by forming and arrangingmany pixels colored in the same color on a substrate in an X-axisdirection as one direction, and forming and arranging pixels such thatpixels adjacent to each other in a Y-axis direction perpendicular to theX-axis direction are colored in different colors, wherein the colorfilter is manufactured by using a plurality of ink-jet heads fordifferent colors, each having a plurality of ink discharging nozzlesarranged in the Y-axis direction, each ink-jet head having a first inkdischarging nozzle group, in which a pitch of the plurality of inkdischarging nozzles in the Y-axis direction is set to be equal to apitch of the pixels of the same color in the Y-axis direction, and asecond ink discharging nozzle group having a nozzle pitch set to beequal to the pixel pitch in the Y-axis direction like the first inkdischarging nozzle group, moving means for moving the relative positionsof the plurality of ink-jet heads and the substrate, and control meansfor controlling an operation of the moving means and ink dischargingoperations of the plurality of ink-jet heads, and causing each of theink-jet heads to discharge an ink while scanning the ink-jet head in theX-axis direction, and coloring all the pixels by scanning the ink-jethead once or a plurality of numbers of times in the X-axis direction.

A display device of the present invention is characterized by thefollowing arrangement according to its first aspect.

There is provided a display device using a color filter manufactured byforming and arranging many pixels colored in the same color on asubstrate in an X-axis direction as one direction, and periodicallyforming and arranging pixels such that pixels adjacent to each other ina Y-axis direction perpendicular to the X-axis direction are colored indifferent colors, integrally comprising a color filter manufactured byusing a plurality of ink-jet heads for different colors, each having aplurality of ink discharging nozzles arranged in the Y-axis direction,each ink-jet head having a first ink discharging nozzle group, in whicha pitch of the plurality of ink discharging nozzles in the Y-axisdirection is set to be equal to a pitch of the pixels of the same colorin the Y-axis direction, and a second ink discharging nozzle grouphaving a nozzle pitch set to be equal to the pixel pitch in the Y-axisdirection like the first ink discharging nozzle group, moving means formoving the relative positions of the plurality of ink-jet heads and thesubstrate, and control means for controlling an operation of the movingmeans and ink discharging operations of the plurality of ink-jet heads,and causing each of the ink-jet heads to discharge an ink while scanningthe ink-jet head in the X-axis direction, and coloring all the pixels byscanning the ink-jet head once or a plurality of numbers of times in theX-axis direction, and light amount changing means for changing a lightamount.

An apparatus including a display device of the present invention ischaracterized by the following arrangement according to its firstaspect.

There is provided an apparatus having a display device using a colorfilter manufactured by forming and arranging many pixels colored in thesame color on a substrate in an X-axis direction as one direction, andperiodically forming and arranging pixels such that pixels adjacent toeach other in a Y-axis direction perpendicular to the X-axis directionare colored in different colors, integrally comprising a display deviceintegrally having a color filter manufactured by using a plurality ofink-jet heads for different colors, each having a plurality of inkdischarging nozzles arranged in the Y-axis direction, each ink-jet headhaving a first ink discharging nozzle group, in which a pitch of theplurality of ink discharging nozzles in the Y-axis direction is set tobe equal to a pitch of the pixels of the same color in the Y-axisdirection, and a second ink discharging nozzle group having a nozzlepitch set to be equal to the pixel pitch in the Y-axis direction likethe first ink discharging nozzle group, moving means for moving therelative positions of the plurality of ink-jet heads and the substrate,and control means for controlling an operation of the moving means andink discharging operations of the plurality of ink-jet heads, andcausing each of the ink-jet heads to discharge an ink while scanning theink-jet head in the X-axis direction, and coloring all the pixels byscanning the ink-jet head once or a plurality of numbers of times in theX-axis direction, and light amount changing means for changing a lightamount, and image signal supply means for supplying an image signal tothe display device.

An ink-jet apparatus of the present invention is characterized by thefollowing arrangement.

There is provided an ink-jet apparatus for coloring a coloring medium byusing a first ink discharging nozzle group, and a second ink dischargingnozzle group capable of discharging an ink in place of the first inkdischarging nozzle, comprising control means for causing only the firstink discharging nozzle group to perform a pre-discharging operationbefore the coloring medium is colored by the first ink dischargingnozzle group, and causing both the first and second ink dischargingnozzle groups to perform a pre-discharging operation at a frequencylower than that of a pre-discharging operation performed by the firstink discharging nozzle group.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its secondaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging a plurality of colored pixels on asubstrate, comprising an ink-jet head having a plurality of inkdischarging nozzles, moving means for moving relative positions of theink-jet head and the substrate, and control means for controlling anoperation of the moving means and an ink discharging operation of theink-jet head, wherein when the ink-jet head is to be scanned a pluralityof numbers of times so as to color the substrate, the control meanscontrols an ink discharging operation such that ink discharging nozzleswhich have been used in a previous scanning operation are always usedentirely or partly in a succeeding scanning operation.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its thirdaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging a plurality of colored pixels on asubstrate, comprising a plurality of ink-jet heads for different colors,each having a plurality of ink discharging nozzles, moving means formoving relative positions of the plurality of ink-jet heads and thesubstrate, and control means for controlling an operation of the movingmeans and ink discharging operations of the ink-jet head, wherein whenthe plurality of ink-jet heads are to be scanned a plurality of numbersof times so as to color an entire area of the substrate, the controlmeans controls an ink discharging operation such that ink dischargingnozzles which have been used in a previous scanning operation are alwaysused entirely or partly in a succeeding scanning operation.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its fourthaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging many pixels colored in the samecolor on a substrate in an X-axis direction as one direction, andperiodically forming and arranging pixels such that pixels adjacent toeach other in a Y-axis direction perpendicular to the X-axis directionare colored in different colors, comprising a plurality of ink-jet headsfor different colors, each having a plurality of ink discharging nozzlesarranged in the Y-axis direction, moving means for moving relativepositions of the plurality of ink-jet heads and the substrate, andcontrol means for controlling an operation of the moving means and inkdischarging operations of the ink-jet head, wherein when the pluralityof ink-jet heads are to be scanned a plurality of numbers of times so asto color an entire area of the substrate, the control means controls anink discharging operation such that ink discharging nozzles which havebeen used in a previous scanning operation are always used entirely orpartly in a succeeding scanning operation.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its fifthaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging many pixels colored in the samecolor on a substrate in an X-axis direction as one direction, andforming and arranging pixels such that pixels adjacent to each other ina Y-axis direction perpendicular to the X-axis direction are colored indifferent colors, comprising a plurality of ink-jet heads for differentcolors, each having a plurality of ink discharging nozzles arranged inthe Y-axis direction, the ink discharging nozzles being arranged at apitch in the Y-axis direction which is equal to a pitch of pixels of thesame color in the Y-axis direction, moving means for moving relativepositions of the plurality of ink-jet heads and the substrate, andcontrol means for controlling an operation of the moving means and inkdischarging operations of the ink-jet head, wherein when the pluralityof ink-jet heads are to be scanned a plurality of numbers of times so asto color an entire area of the substrate, the control means controls anink discharging operation such that ink discharging nozzles which havebeen used in a previous scanning operation are always used entirely orpartly in a succeeding scanning operation.

A color filter manufacturing method of the present invention ischaracterized by the following process according to its second aspect.

There is provided a method of manufacturing a color filter by arranginga plurality of colored pixels on a substrate by controlling relativepositions of an ink-jet head having a plurality of ink dischargingnozzles and the substrate, and discharging an ink from the ink-jet headonto the substrate, comprising in coloring an entire area of thesubstrate by scanning the ink-jet head a plurality of numbers of times,performing an ink discharging operation such that ink dischargingnozzles which have been used in a previous scanning operation are alwaysused entirely or partly in a succeeding scanning operation.

A color filter of the present invention is characterized by thefollowing arrangement according to its second aspect.

There is provided a color filter manufactured by forming and arranging aplurality of colored pixels on a substrate, wherein the color filter ismanufactured by using an ink-jet head having a plurality of inkdischarging nozzles, moving means for moving relative positions of theink-jet head and the substrate, and control means for controlling anoperation of the moving means and an ink discharging operation of theink-jet head, and performing an ink discharging operation such that inkdischarging nozzles which have been used in a previous scanningoperation are always used entirely or partly in a succeeding scanningoperation, in coloring an entire area of the substrate by scanning theink-jet head a plurality of numbers of times.

A display device of the present invention is characterized by thefollowing arrangement according to its second aspect.

There is provided a display device using a color filter manufactured byforming and arranging a plurality of colored pixels on a substrate,integrally comprising a color filter is manufactured by using an ink-jethead having a plurality of ink discharging nozzles, moving means formoving relative positions of the ink-jet head and the substrate, andcontrol means for controlling an operation of the moving means and anink discharging operation of the ink-jet head, and performing an inkdischarging operation such that ink discharging nozzles which have beenused in a previous scanning operation are always used entirely or partlyin a succeeding scanning operation, in coloring an entire area of thesubstrate by scanning the ink-jet head a plurality of numbers of times,and light amount changing means for changing a light amount.

An apparatus including a display device of the present invention ischaracterized by the following arrangement according to its secondaspect.

There is provided an apparatus having a display device using a colorfilter manufactured by forming and arranging a plurality of coloredpixels on a substrate, comprising a display device integrally having acolor filter is manufactured by using an ink-jet head having a pluralityof ink discharging nozzles, moving means for moving relative positionsof the ink-jet head and the substrate, and control means for controllingan operation of the moving means and an ink discharging operation of theink-jet head, and performing an ink discharging operation such that inkdischarging nozzles which have been used in a previous scanningoperation are always used entirely or partly in a succeeding scanningoperation, in coloring an entire area of the substrate by scanning theink-jet head a plurality of numbers of times, and light amount changingmeans for changing a light amount, and image signal output means foroutputting an image signal to the display device.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its sixthaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging many colored pixels on asubstrate, comprising ink discharging means having a plurality of inkdischarging nozzles, moving means for moving relative positions of theink discharging means and the substrate, and control means forcontrolling an operation of the moving means and an ink dischargingoperation of the ink discharging means, wherein when the ink dischargingmeans is to be scanned a plurality of numbers of times to color thesubstrate, the control means controls such that the numbers of nozzlesused for coloring in the respective scanning operations becomesubstantially equal to each other.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its seventhaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging many colored pixels on asubstrate, comprising a plurality of ink discharging means for differentcolors, each having a plurality of ink discharging nozzles, moving meansfor moving relative positions of the plurality of ink discharging meansand the substrate, and control means for controlling an operation of themoving means and ink discharging operations of the plurality of inkdischarging means, wherein when the plurality of ink discharging meansare to be scanned a plurality of numbers of times to color an entirearea of the substrate, the control means controls such that the numbersof nozzles used for coloring in the respective scanning operationsbecome substantially equal to each other.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its eightaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging many pixels colored in the samecolor on a substrate in an X-axis direction as one direction, andforming and arranging pixels such that pixels adjacent to each other ina Y-axis direction perpendicular to the X-axis direction are colored indifferent colors, comprising a plurality of ink discharging means fordifferent colors, each having a plurality of ink discharging nozzlesarranged in the Y-axis direction, moving means for moving relativepositions of the plurality of ink discharging means and the substrate,and control means for controlling an operation of the moving means andink discharging operations of the plurality of ink discharging means,wherein when the plurality of ink discharging means are to be scanned aplurality of numbers of times to color an entire area of the substrate,the control means controls such that the numbers of nozzles used forcoloring in the respective scanning operations become substantiallyequal to each other.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its ninthaspect.

There is provided a manufacturing apparatus for a color filtermanufactured by forming and arranging many pixels colored in the samecolor on a substrate in an X-axis direction as one direction, andforming and arranging pixels such that pixels adjacent to each other ina Y-axis direction perpendicular to the X-axis direction are colored indifferent colors, comprising a plurality of ink discharging means fordifferent colors, each having a plurality of ink discharging nozzlesarranged in the Y-axis direction, the ink discharging means havingnozzle arrays in which at least a pitch of the plurality of inkdischarging nozzles in the Y-axis direction is set to be equal to apitch of pixels of the same color in the Y-axis direction, moving meansfor moving relative positions of the plurality of ink discharging meansand the substrate, and control means for controlling an operation of themoving means and ink discharging operations of the plurality of inkdischarging means, wherein when the plurality of ink discharging meansare to be scanned a plurality of numbers of times to color an entirearea of the substrate, the control means controls such that the numbersof nozzles used for coloring in the respective scanning operationsbecome substantially equal to each other.

A color filter manufacturing method of the present invention ischaracterized by the following process according to its third aspect.

There is provided a manufacturing method for a color filter manufacturedby forming and arranging many colored pixels on a substrate, comprisingin coloring an entire area of the substrate by performing a scanningoperation of moving relative positions of an ink discharging meanshaving a plurality of ink discharging nozzles and the substrate aplurality of numbers of times, performing a coloring operation such thatthe numbers of nozzles used for coloring in the respective scanningoperations become substantially equal to each other.

A color filter of the present invention is characterized by thefollowing arrangement according to its third aspect.

There is provided a color filter manufactured by forming and arrangingmany colored pixels on a substrate, wherein when an entire area of thesubstrate is to be colored by performing a scanning operation of movingrelative positions of an ink discharging means having a plurality of inkdischarging nozzles and the substrate a plurality of numbers of times, acoloring operation is performed such that the numbers of nozzles usedfor coloring in the respective scanning operations become substantiallyequal to each other.

A display device of the present invention is characterized by thefollowing arrangement according to its third aspect.

There is provided a display device using a color filter manufactured byforming and arranging many colored pixels on a substrate, integrallycomprising a color filter manufactured by performing a coloringoperation such that the numbers of nozzles used for coloring in therespective scanning operations become substantially equal to each otherwhen an entire area of the substrate is to be colored by performing ascanning operation of moving relative positions of an ink dischargingmeans having a plurality of ink discharging nozzles and the substrate aplurality of numbers of times, and light amount changing means forchanging a light amount.

An apparatus including a display device of the present invention ischaracterized by the following arrangement according to its thirdaspect.

There is provided an apparatus having a display device using a colorfilter manufactured by forming and arranging many colored pixels on asubstrate, comprising a display device integrally having a color filtermanufactured by performing a coloring operation such that the numbers ofnozzles used for coloring in the respective scanning operations becomesubstantially equal to each other when an entire area of the substrateis to be colored by performing a scanning operation of moving relativepositions of an ink discharging means having a plurality of inkdischarging nozzles and the substrate a plurality of numbers of times,and light amount changing means for changing a light amount, and imagesignal output means for outputting an image signal to the displaydevice.

A color filter manufacturing method of the present invention ischaracterized by the following process according to its fourth aspect.

There is provided a color filter manufacturing method of dividing allink discharging nozzles of an ink-jet head having the plurality of inkdischarging nozzles into a plurality of nozzle groups each including apredetermined number of nozzles, discharging an ink upon switching theplurality of nozzle groups as needed, and coloring each pixel of a colorfilter, comprising the switching step of switching the plurality ofnozzle groups, and the compensation step of compensating for apositional offset between a nozzle group to be used and each pixel.

A color filter manufacturing apparatus of the present invention ischaracterized by the following arrangement according to its tenthaspect.

There is provided a color filter manufacturing apparatus for dividingall ink discharging nozzles of an ink-jet head having the plurality ofink discharging nozzles into a plurality of nozzle groups each includinga predetermined number of nozzles, discharging an ink upon switching theplurality of nozzle groups as needed, and coloring each pixel of a colorfilter, comprising switching means for switching the plurality of nozzlegroups, control means for controlling a switching operation of theswitching means, and compensation means for, when the nozzle groups areswitched by the switching means, compensating for a positional offsetbetween the nozzle group to be used and each pixel.

Other objects and advantages besides those discussed above shall beapparent to those skilled in the art from the description of a preferredembodiment of the invention which follows. In the description, referenceis made to accompanying drawings, which form a part hereof, and whichillustrate an example of the invention. Such example, however, is notexhaustive of the various embodiments of the invention, and thereforereference is made to the claims which follow the description fordetermining the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the relationship between a color filter and anink-jet head in a color manufacturing apparatus;

FIGS. 2A to 2F are sectional views for explaining a color filtermanufacturing process;

FIGS. 3A to 3F are sectional views for explaining another color filtermanufacturing process;

FIG. 4 is a sectional view showing the structure of a TFT liquid crystalpanel incorporating a color filter manufactured by a manufacturingapparatus of an embodiment of the present invention;

FIG. 5 is a sectional view showing the structure of a TFT liquid crystalpanel incorporating a color filter manufactured by the manufacturingapparatus of an embodiment of the present invention;

FIG. 6 is a block diagram showing an information processing apparatususing a liquid crystal panel;

FIG. 7 is a perspective view showing the information processingapparatus using the liquid crystal panel;

FIG. 8 is a perspective view showing an information processing apparatususing a liquid crystal panel;

FIG. 9 is a view showing the pattern of a color filter manufactured bythe manufacturing apparatus of the embodiment;

FIG. 10 is a view showing the size of the display unit of a TFT liquidcrystal panel incorporating a color filter manufactured by themanufacturing apparatus of the embodiment;

FIG. 11 is a perspective view showing the structure of an ink-jet head;

FIG. 12 is a view showing the arrangement of a restoring unit for themanufacturing apparatus of the embodiment;

FIG. 13 is a view showing a state wherein the restoring unit for themanufacturing apparatus of the embodiment is performing a cappingoperation;

FIG. 14 is a view showing a state wherein the restoring unit for themanufacturing apparatus of the embodiment is performing a wipingoperation;

FIG. 15 is a perspective view showing the structure of an ink-jet head;

FIG. 16 is a block diagram showing the schematic arrangement of themanufacturing apparatus of the embodiment;

FIG. 17 is a flow chart schematically showing the operation of themanufacturing apparatus of the embodiment;

FIG. 18 is a view showing how ink-jet heads are moved relative to aglass substrate in the manufacturing apparatus of the embodiment;

FIG. 19 is a view showing the positional relationship between each pixeland each discharging nozzle in the manufacturing apparatus of theembodiment;

FIG. 20 is a view showing how ink-jet head discharges an ink;

FIG. 21 is a view showing the arrangement of the discharging nozzles onthe nozzle surface of an ink-jet head;

FIG. 22 is a view showing the arrangement of the discharging nozzles onthe nozzle surface of an ink-jet head;

FIG. 23 is a view showing how ink-jet heads are moved relative to aglass substrate in a manufacturing apparatus of another embodiment;

FIG. 24 is a view showing how ink-jet heads are moved relative to aglass substrate in a manufacturing apparatus of still anotherembodiment;

FIG. 25 is a view showing the arrangement of a color filtermanufacturing apparatus of the fifth embodiment of the presentinvention;

FIG. 26 is a view showing the arrangement of a color filtermanufacturing apparatus of the sixth embodiment of the presentinvention; and

FIG. 27 is a view showing the arrangement of a color filtermanufacturing apparatus of the seventh embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention will be described indetail below with reference to the accompanying drawings.

First Embodiment

FIGS. 2A to 2F show a color filter manufacturing process using a colorfilter manufacturing apparatus according to an embodiment of the presentinvention.

In this embodiment, as a substrate 1, a glass substrate is generallyused. However, a substrate other than a glass substrate can be used aslong as it has characteristics required for a liquid crystal colorfilter, e.g., good transparency and high mechanical strength.

First of all, the glass substrate 1 is prepared, on which a black matrix2 is formed to clearly partition off each pixel of a color filter so asto obtain a clear image (FIG. 2A). As a method of forming a blackmatrix, a method of forming a thin metal film on a substrate bysputtering or deposition, and patterning the film by a photolithographicprocess is available.

As shown in FIG. 2B, a coating material is applied to the substrate 1,on which the black matrix 2 is formed. The resultant structure ispre-baked, as needed, to form a resin composition layer 3. Uponirradiation of light or irradiation of light and a heat treatment, theink absorption property of the irradiated portions of the resincomposition layer 3 improves. As the coating material, the followingresin composition is used. Upon exposure or exposure and a heattreatment, the ink absorption property of the exposed portions of theresin composition improves. By using the difference in ink absorptionproperty between the exposed and non-exposed portions, color mixing ofinks and the unnecessary diffusion of an ink can be prevented.

Pattern exposure is performed, via a mask 4, with respect to the coatingmaterial on the portions which are not light-shielded by the blackmatrix 2 to perform an ink affinity process (FIG. 2C), thereby forming alatent image (FIG. 2D).

Subsequently, ink-jet heads are used to discharge R (red), G (green),and B (blue) inks onto portions 6 having affinities for inks (FIG. 2E),and the inks are dried, as needed.

Irradiation of light or a heat treatment and irradiation of light areperformed to cure the colored coating material, and a protective layer 8is formed as needed (FIG. 2F). The protective layer 8 can be made of,e.g., a resin material of a photo-setting type, thermosetting type, orphoto-setting/thermosetting type, or an inorganic film formed bydeposition or sputtering. The resultant layer needs to have transparencyupon formation of a color filter and be sufficiently resistant to thesubsequent processes such as an ITO (Indium Tin Oxide) formation processand an aligning film formation process.

FIGS. 3A to 3F are views showing another color filter manufacturingprocess.

FIG. 3A shows a glass substrate 1 having a black matrix 2 constituted bylight-transmitting portions 7 and light-shielding portions. First ofall, the glass substrate 1, on which the black matrix 2 is formed, iscoated with a resin composition which can be cured upon irradiation oflight or irradiation of light and heating, and exhibits ink receptivity.The resultant structure is pre-baked, as needed, to form a resincomposition layer 3′ (FIG. 3B). The resin composition layer 3′ can beformed by a coating method such as spin coating, roller coating, barcoating, spraying, or dipping. However, a coating method to be used isnot specifically limited.

Subsequently, pattern exposure is performed by using a photomask 4′ withrespect to the resin layer portions which are light-shielded by theblack matrix 2 to partly cure the resin layer, thereby forming portions5′ (non-colored portions) which do not absorb an ink (FIG. 3C).Thereafter, the resin layer is colored in R, G, and B at once by usingthe ink-jet heads (FIG. 3D), and the inks are dried, as needed.

As the photomask 4′ used when pattern exposure is performed, a maskhaving opening portions for curing the portions light-shielded by theblack matrix is used. In this case, in order to prevent a color omissionof the color material at a portion in contact with the black matrix, arelatively large amount of ink must be discharged. For this reason, amask having opening portions each having a size smaller than the widthof each light-shielding portion of the black matrix.

As an ink to be used for a coloring operation, either of dye and pigmentinks can be used, and either of liquid and solid inks can be used.

As a curable resin composition to be used in the present invention, anyresin composition which has ink receptivity and can be cured by at leastone of the following treatments: irradiation of light and a combinationof irradiation of light and heating, can be used. As resins, acrylicresin, epoxy resin, and silicone resin are available. As cellulosederivatives, hydroxypropyl cellulose, hydroxy ethyl cellulose, methylcellulose, carboxymethyl cellulose are available, and modified materialsare available.

Optical initiators (crosslinkers) can also be used to make crosslinkingreactions of these resins proceed upon irradiation of light orirradiation of light and heat. As optical initiators, dichromate, abis-azide compound, a radical-based initiator, a cation-based initiator,an anion-based initiator, and the like can be used. Mixtures of theseoptical initiators and combinations of the initiators and sensitizerscan also be used. In addition, an optical acid generating agent such asonium salt can be used as a crosslinker. In order to make a crosslinkingreaction further proceed, a heat treatment may be performed afterirradiation of light.

Resin layers containing these compositions have excellent heatresistance, excellent water resistance, and the like, and aresufficiently resistant to high temperatures and cleaning in thesubsequent steps.

As an ink-jet system used in the present invention, a bubble-jet typeusing an electrothermal converter as an energy generating element, apiezoelectric jet type using a piezoelectric element, or the like can beused. A coloring area and coloring pattern can be arbitrarily set.

This embodiment exemplifies the structure in which the black matrix isformed on the substrate. However, after a curable resin compositionlayer is formed or after coloring is performed, a black matrix may beformed on the resin layer without posing any problem. That is, the formof a black matrix is not limited to that in this embodiment. As a methodof forming a black matrix, a method of forming a thin metal film on asubstrate by sputtering or deposition, and patterning the film by aphotolithographic process is preferably used. However, the presentinvention is not limited to this.

Subsequently, the curable resin composition is cured by performing onlyone of the following treatments: irradiation of light, a heat treatment,and a combination of irradiation of light and a heat treatment (FIG.3E), and a protective layer 8 is formed, as needed (FIG. 3F). Note thatreference symbol hν denotes the intensity of light. When a heattreatment is to be performed, heat is applied instead of hν. Theprotective layer 8 can be made of a second resin composition of aphoto-setting type, thermosetting type, or photo-setting/thermosettingtype. The resultant layer needs to have transparency upon formation of acolor filter and be sufficiently resistant to the subsequent processessuch as an ITO formation process and an aligning film formation process.

FIGS. 4 and 5 are sectional views each showing a TFT (Thin FilmTransistor) color liquid crystal panel incorporating the color filter ofthis embodiment. Note that the form of a color liquid crystal panel isnot limited to any of these examples.

In general, a color liquid crystal panel is formed by joining a colorfilter substrate 1 to a counter substrate 254 and sealing a liquidcrystal compound 252 therebetween. TFTs (Thin Film Transistors) (notshown) and transparent pixel electrodes 253 are formed on the innersurface of one substrate 254 of the liquid crystal panel in a matrixform. A color filter 10 is placed on the inner surface of the othersubstrate 12 such that the R, G, and B coloring materials are positionedto oppose the pixel electrodes. A transparent counter electrode (commonelectrode) 250 is formed on the entire surface of the color filter 10. Ablack matrix 2 is generally formed on the color filter substrate 1 side(see FIG. 4). However, in a BM (Black Matrix) on-array type liquidcrystal panel, the black matrix is formed on the TFT substrate sideopposing the color filter substrate (see FIG. 5). In addition, aligningfilms 251 are formed within the planes of the two substrates. Byperforming a rubbing process for the aligning films 251, the liquidcrystal molecules can be aligned in a predetermined direction.Polarizing plates 255 are bonded to the outer surface of the respectiveglass substrates. The liquid crystal compound 252 is filled in the gap(about 2 to 5 μm) between these glass substrates. As a blacklight, acombination of a fluorescent lamp (not shown) and a scattering plate(not shown) is generally used. A display operation is performed bycausing the liquid crystal compound to serve as an optical shutter forchanging the transmittance for light emitted from the backlight.

A case wherein the above liquid crystal display device is applied to aninformation processing apparatus will be described below with referenceto FIGS. 6 to 8.

FIG. 6 is a block diagram showing the schematic arrangement of aninformation processing apparatus serving as a wordprocessor, a personalcomputer, a facsimile apparatus, and a copying machine, to which theabove liquid crystal display device is applied.

Referring to FIG. 6, reference numeral 1801 denotes a control unit forcontrolling the overall apparatus. The control unit 1801 includes a CPUsuch as a microprocessor and various I/O ports, and performs control byoutputting/inputting control signals, data signals, and the like to/fromthe respective units. Reference numeral 1802 denotes a display unit fordisplaying various menus, document information, and image data read byan image reader 1807, and the like on the display screen; 1803, atransparent, pressure-sensitive touch panel mounted on the display unit1802. By pressing the surface of the touch panel 1803 with a finger ofthe user or the like, an item input operation, a coordinate positioninput operation, or the like can be performed on the display unit 1802.

Reference numeral 1804 denotes an FM (Frequency Modulation) sound sourceunit for storing music information, created by a music editor or thelike, in a memory unit 1810 or an external memory unit 1812 as digitaldata, and reading out the information from such a memory, therebyperforming FM modulation of the information. An electrical signal fromthe FM sound source unit 1804 is converted into an audible sound by aspeaker unit 1805. A printer unit 1806 is used as an output terminal forthe wordprocessor, the personal computer, the facsimile apparatus, andthe copying machine.

Reference numeral 1807 denotes an image reader unit forphotoelectrically reading original data. The image reader unit 1807 isarranged midway along the original convey passage and designed to readoriginals for facsimile and copy operations and other various originals.

Reference numeral 1808 denotes a transmission/reception unit for thefacsimile (FAX) apparatus. The transmission/reception unit 1808transmits original data read by the image reader unit 1807 by facsimile,and receives and decodes a sent facsimile signal. Thetransmission/reception unit 1808 has an interface function for externalunits. Reference numeral 1809 denotes a telephone unit having a generaltelephone function and various telephone functions such as an answeringfunction.

Reference numeral 1810 denotes a memory unit including a ROM for storingsystem programs, manager programs, application programs, fonts, anddictionaries, a RAM for storing an application program loaded from theexternal memory unit 1812 and document information, a video RAM, and thelike.

Reference numeral 1811 denotes a keyboard unit for inputting documentinformation and various commands.

Reference numeral 1812 denotes an external memory unit using a floppydisk, a hard disk, and the like. The external memory unit 1812 serves tostore document information, music and speech information, applicationprograms of the user, and the like.

FIG. 7 is a perspective view of the information processing apparatus inFIG. 6.

Referring to FIG. 7, reference numeral 1901 denotes a flat panel displayusing the above liquid crystal display device, which displays variousmenus, graphic pattern information, document information, and the like.A coordinate input or item designation input operation can be performedon the flat panel display 1901 by pressing the surface of the touchpanel 1803 with a finger of the user or the like. Reference numeral 1902denotes a handset used when the apparatus is used as a telephone set. Akeyboard 1903 is detachably connected to the main body via a cord and isused to perform various document functions and input various data. Thiskeyboard 1903 has various function keys 1904. Reference numeral 1905denotes an insertion port through which a floppy disk is inserted intothe external memory unit 1812.

Reference numeral 1906 denotes an original table on which an original tobe read by the image reader unit 1807 is placed. The read original isdischarged from the rear portion of the apparatus. In a facsimilereceiving operation or the like, received data is printed out by anink-jet printer 1907.

When the above information processing apparatus is to serve as apersonal computer or a wordprocessor, various kinds of information inputthrough the keyboard unit 1811 are processed by the control unit 1801 inaccordance with a predetermined program, and the resultant informationis output, as an image, to the printer unit 1806.

When the information processing apparatus is to serve as the receiver ofthe facsimile apparatus, facsimile information input through thetransmission/reception unit 1808 via a communication line is subjectedto reception processing in the control unit 1801 in accordance with apredetermined program, and the resultant information is output, as areceived image, to the printer unit 1806.

When the information processing apparatus is to serve as the copyingmachine, an original is read by the image reader unit 1807, and the readoriginal data is output, as an image to be copied, to the printer unit1806 via the control unit 1801. Note that when the informationprocessing apparatus is to serve as the receiver of the facsimileapparatus, original data read by the image reader unit 1807 is subjectedto transmission processing in the control unit 1801 in accordance with apredetermined program, and the resultant data is transmitted to acommunication line via the transmission/reception unit 1808.

Note that the above information processing apparatus may be designed asan integrated apparatus incorporating an ink-jet printer in the mainbody, as shown in FIG. 8. In this case, the portability of the apparatuscan be improved. The same reference numerals in FIG. 8 denote partshaving the same functions as those in FIG. 7.

FIG. 9 shows the color pattern of a color filter manufactured by thecolor filter manufacturing apparatus of this embodiment. Each of theportions colored by R, G, and B inks is a pixel, which has an almostrectangular shape. Assume that the longitudinal direction of one pixelis the X direction, and a direction perpendicular to the X direction isthe Y direction. All the pixels have the same size, i.e., 150 μm×60 μm.The pitch in the X direction is 300 μm, and the pitch in the Y directionis 100 g m. Pixels of the same color are arranged in a row in the Xdirection, and pixels are arranged in the Y direction such that adjacentpixels have different colors. The pattern shown in FIG. 9 corresponds tothe pattern of the black matrix formed in the step shown in FIG. 2A.

The number of pixels in the X direction is 480, and that in the Ydirection is 1,920 (640 pixels of each color). As shown in FIG. 10, thescreen of the color filter has a size of 144 mm×192 mm, whichcorresponds to a 9.4-inch liquid crystal panel having a diagonal lengthof 240 mm.

FIG. 11 shows the arrangement of a manufacturing apparatus formanufacturing the color filter in FIG. 9.

Referring to FIG. 11, a manufacturing apparatus 20 comprises an X-Ytable 22 mounted on a base (not shown) and capable of moving in the Xand Y directions in FIG. 11, and an ink-jet head IJH fixed on the basevia a support member (not shown) above the X-Y table 22. A glasssubstrate 1 on which a black matrix 2 and a resin composition layer 3are formed in advance by the above method is placed on the X-Y table 22.The ink-jet head IJH includes a red head 120 a for discharging a redink, a green head 120 b for discharging a green ink, and a blue head 120c for discharging a blue ink. These heads 120 a, 120 b, and 120 c aredesigned to discharge inks independently.

A restoring unit 30 for performing a restoring operation for the ink-jethead IJH is provided on an end portion of the X-Y table 22 to be movablein the Z direction with respect to the X-Y table 22.

The restoring unit 30 has a function of preventing clogging of eachnozzle of the ink-jet head IJH and removing an ink or dust adhering toeach nozzle surface of the ink-jet head IJH to always allow a proper inkdischarging operation, and a function of preventing the manufacture of adefective product by preventing dust adhering to each nozzle surfacefrom falling onto a glass substrate during a coloring operation. FIG. 12shows the arrangement of the restoring unit 30.

Reference numerals 31 a, 31 b, and 31 c denote caps corresponding to thered, green, and blue heads 120 a, 120 b, and 120 c of the ink-jet headIJH. While the ink-jet heads 120 a, 120 b, and 120 c are not performingcolor filter coloring operations with respect to the glass substrate 1,the caps 31 a, 31 b, and 31 c respectively cover the nozzle surfaces ofthe ink-jet heads 120 a, 120 b, and 120 c to prevent the heads frombeing incapable of discharging the inks. Assume that the dischargingoperations of the ink-jet heads 120 a, 120 b, and 120 c are resumedafter a predetermined idle time. In this case, even if the above caps 31a, 31 b, and 31 c are used, owing to the influence of an increase in theviscosity of each ink, a discharge failure or twisting may occur indischarging first some inks. That is, first some inks to be dischargedfrom one nozzle may not be discharged or may curve through the air. Inthis case, after not less than a predetermined amount of ink isdischarged, a normal state is restored, and the ink is dischargedstraight. If such a failure occurs while the glass substrate 1 iscolored, some pixels cannot be colored, or the ink does not land atcorrect positions, resulting in a defective product. In order to preventsuch a phenomenon, a predetermined amount of ink is discharged from eachhead, i.e., a pre-discharging operation is performed, before the glasssubstrate 1 is colored.

In this embodiment, this pre-discharging operation is performed by usingthe caps. However, dedicated ink-receiving portions for pre-dischargingmay be formed in other portions.

The caps 31 a, 31 b, and 31 c also have a function of capping theink-jet heads 120 a, 120 b, and 120 c and receiving inks from therespective nozzles so as to prevent the nozzles from dischargingexcessive amounts of inks when an operation (pressuring/restoringoperation) of keeping the ink-jet heads 120 a, 120 b, and 120 c in anormal state is to be performed by periodically pressuring orcirculating inks from the ink supply side to the ink-jet heads 120 a,120 b, and 120 c using an ink pressuring motor (not shown) and forciblydischarging bubbles and dust, which cause discharge failures, from thenozzles.

Reference numerals 32 a, 32 b, and 32 c denote blades for wiping thenozzle surfaces. Each blade preferably has water absorption property. Asshown in FIG. 14, with the operation of the restoring unit 30 in the Xdirection, the blades 32 a, 32 b, and 32 c wipe off the ink adhering tothe nozzle surfaces of the ink-jet heads 120 a, 120 b, and 120 c or inkmists which are produced upon discharging of inks and adhere to thenozzle surfaces.

Reference numeral 33 denotes a restoring pail disposed below the caps 31a, 31 b, and 31 c and the blades 32 a, 32 b, and 32 c to prevent inksleaking from the caps or cap and blade cleaning solutions (to bedescribed later) from leaking into the apparatus. Inks and cleaningsolutions stored in the restoring pail 33 are guided into a drainagebath 37. The restoring pail 33 is designed to operate integrally withthe caps 31 a, 31 b, and 31 c and the blades 32 a, 32 b, and 32 c. Whena capping operation in the Z direction and a wiping operation in the Xdirection are performed, the restoring pail 33 operates in the samemanner as the caps 31 a, 31 b, and 31 c, and the blades 32 a, 32 b, and32 c.

Reference numerals 34 a, 34 b, and 34 c denote open valves. One end ofeach open valve communicates with a corresponding one of the caps 31 a,31 b, and 31 c via tubes. The other end of each open valve is set at theatmospheric pressure. The caps 31 a, 31 b, and 31 c are made of rubberand pressed against the respective heads with a force of about 1 kgf ormore, and then the volume of each cap decreases. The internal pressureof each cap exceeds the atmospheric pressure. As a result, an ink ineach nozzle is pushed into each ink-jet head, causing a dischargefailure. The open valves 34 a, 34 b, and 34 c are arranged to preventsuch a phenomenon. Each open valve is closed in a normal operation.Before a capping operation, each open valve is opened. By keeping eachopen valve closed after a capping operation, the inside of each cap canbe kept at the atmospheric pressure.

Reference numeral 35 denotes a cap suction pump for sucking an inkstored in each cap in a pressuring/restoring operation, and sucking anink pre-discharged into each cap. The cap suction pumps 35 arerespectively connected to the caps 31 a, 31 b, and 31 c via tubes. Thesucked inks are discharged into the drainage bath 37.

Reference numeral 36 denotes blade suction pumps 36 for sucking waterabsorbed by the blades 32 a, 32 b, and 32 c each made of a materialhaving water absorption property, and sucking inks absorbed in a wipingoperation. The blade suction pumps 36 are respectively connected to theblades 32 a, 32 b, and 32 c via tubes. The absorbed water and inks aredischarged into the drainage bath 37. The water and inks discharged intothe drainage bath 37 are discharged outside the apparatus altogether.

Reference numeral 38 (see FIG. 12) denotes a washing water tank forstoring washing water for washing the caps 31 a, 31 b, and 31 c and theblades 32 a, 32 b, and 32 c. When a washing water supply valve 39 isopened, washing water is sprayed from each washing water supply nozzle40. Referring to FIG. 11, these washing water supply nozzles 40 arepositioned immediately above the restoring unit 30 when the ink-jet headIJH (120 a, 120 b, and 120 c) completely colors the glass substrate 1.

Reference numeral 41 (see FIG. 12) denotes a washing water replenishmentvalve for replenish washing water into the washing water tank 38. When awashing water residue detection sensor 42 detects that the amount ofwashing water in the washing water tank 38 becomes small, the washingwater replenishment valve 41 is kept open for a predetermined period oftime to replenish washing water into the washing water tank 38. As thiswashing water, distilled water obtained by removing impurities from tapwater is used.

FIG. 15 shows the structure of the ink-jet head IJH for discharging anink onto the resin composition layer 3. Since these three ink-jet heads120 a, 120 b, and 120 c have the same structure, FIG. 15 shows thestructure of one of them as a representative.

Referring to FIG. 15, the ink-jet head IJH mainly comprises a heaterboard 104 as a board on which a plurality of heaters 102 for heating anink are formed, and a ceiling plate 106 mounted on the heater board 104.A plurality of discharging openings 108 are formed in the ceiling plate106. Tunnel-like fluid passages 110 communicating with the dischargingopenings 108 are formed therebehind. The respective fluid passages 110are isolated from the adjacent fluid passages via partition walls 112.The respective fluid passages 110 are commonly connected to one inkchamber 114 at the rear side of the fluid passages. An ink is suppliedto the ink chamber 114 via an ink inlet 117. This ink is supplied fromthe ink chamber 114 to each fluid passage 110.

The heater board 104 and the ceiling plate 106 are positioned such thatthe position of each heater 102 coincides with that of a correspondingfluid passage 110, and are assembled into the state shown in FIG. 15.Although FIG. 15 shows only two heaters 102, the heater 102 is arrangedin correspondence with each fluid passage 110. When a predetermineddriving signal is supplied to the heater 102 in the assembled stateshown in FIG. 15, an ink above the heater 102 is boiled to produce abubble, and the ink is pushed and discharged from the dischargingopening 108 upon volume expansion of the ink.

FIG. 16 is a block diagram showing the arrangement of the color filtermanufacturing apparatus of this embodiment.

Referring to FIG. 16, X- and Y-direction driving motors 56 and 58 fordriving the X-Y table 22 in the X and Y directions are connected to aCPU 50 for controlling the overall operation of the manufacturingapparatus via X and Y motor driving circuits 52 and 54. A Z-directiondriving motor 59 for driving the restoring unit 30 in the Z direction isconnected to the CPU 50 via a Z motor driving circuit 55.

The ink-jet head IJH is also connected to the CPU 50 via a head drivingcircuit 60. Furthermore, X and Y encoders 62 and 64 for detecting theposition of the X-Y table 22 is connected to the CPU 50. With thisarrangement, position information of the X-Y table 22 is input to theCPU 50. In addition, a control program in a program memory 66 is inputto the CPU 50. The CPU 50 moves the X-Y table 22 in accordance with thiscontrol program and position information from the X and Y encoders 62and 64. With this operation, a desired grating frame (pixel) on theglass substrate 1 is brought to a position below the ink-jet head IJH,and an ink having a desired color is discharged into the pixel to colorit, thereby coloring the glass substrate 1. A color filter ismanufactured by performing this operation for each pixel. Every timecoloring of one glass substrate 1 is completed, the restoring unit 30mounted on an end portion of the X-Y stage 22 is moved to a positionimmediately below the ink-jet head IJH, and the blades 32 a, 32 b, and32 c are moved in the X direction by the X-direction driving motor 56 toperform a wiping operation. In addition, the caps 31 a, 31 b, and 31 care moved in the Z direction by the Z-direction driving motor 59 toperform a pre-discharging operation. Meanwhile, the colored glasssubstrate 1 is replaced with a new glass substrate 1 by a substrateconvey unit (not shown).

The operation of the color filter manufacturing apparatus of thisembodiment will be described next with reference to FIG. 17.

In step S1, inks are discharged from the ink-jet head IJH onto the glasssubstrate 1 to color one glass substrate 1. When coloring of onesubstrate is completed, the X-Y stage 22 is operated to move therestoring unit 30 to the position of each washing water supply nozzle40, and washing water is sprayed against the blades 32 a, 32 b, and 32c, thereby washing the blades (step S2). The X-Y stage 22 is then movedto move the restoring unit 30 to the position of the ink-jet head IJH(step S3). If it is determined in step S4 that the number of coloredsubstrates is less than a predetermined number, a normal wipingoperation is performed by using the blades 32 a, 32 b, and 32 c to wipeoff ink mists adhering to the nozzle surfaces (step S5). If it isdetermined in step S4 that not less than a predetermined number ofsubstrates are colored, a pressuring/restoring operation is performed toremove an ink with increased viscosity in each nozzle and bubbles in theink chamber (step S6). In this embodiment, every time 30 glasssubstrates are colored, a pressuring/restoring operation is performed.This pressuring/restoring operation is performed only to discard inkswithout using them for a coloring operation, and requires an increase inthe number of steps, demanding a corresponding period of time. For thisreason, the number of times this operation is performed is preferablyminimized.

When a pressuring/restoring operation is performed, an ink adheres tothe nozzle surfaces. For this reason, a wiping operation for apressuring operation is performed afterward (step S7). Since the inkdischarged from the nozzles adheres to the caps in thepressuring/restoring operation (step S6), a cap washing operation isperformed (step S8). It is checked whether the coloring operation isterminated for maintenance of the apparatus or the like (step S9). If itis determined that the coloring operation is terminated, the cappingoperation and the like are terminated (step S12) to terminate thecoloring operation. If it is determined that the coloring operation iscontinued, the ink-jet heads 120 a, 120 b, and 120 c are capped, andeach ink-jet head performs a pre-discharging operation to discharge apredetermined number of inks (step S10). Thereafter, a cap washingoperation is performed to wash away the inks pre-discharged and adheringto the caps (step S11). While these restoring operations are performed,the colored substrate is replaced with a new substrate, and the nextcoloring operation is performed. This process is repeated.

Characteristic features of the present invention in coloring a glasssubstrate will be described next with reference to FIGS. 18 and 19.

Each of the heads 120 a, 120 b, and 120 c of the ink-jet head IJH inFIG. 18 has 512 effective nozzles, and a nozzle pitch of 70.5 μm. Thatis, each ink-jet head has a resolution of 360 dpi. As shown in FIG. 9,according to the color filter of this embodiment, the pixels of eachcolor are arranged at a pitch of 300 μm. Since the pixel pitch isdifferent from the nozzle pitch of the ink-jet head IJH, every fivenozzles of the ink-jet head IJH are used. That is, as shown in FIG. 18,only 120 nozzles of the 512 nozzles of the ink-jet head IJH are used.For this reason, the ink-jet head IJH is tilted at 31.672°, as shown inFIG. 18. FIG. 19 shows the positional relationship between the pixels ofthe respective colors and the nozzles of the ink-jet head IJH. Of thenozzles 108 of each of the ink-jet heads 120 a, 120 b, and 120 c, onlyevery five nozzles indicated by the solid lines are located above thepixels of the corresponding colors. The remaining nozzles indicated bythe broken lines are located outside the pixels of the correspondingcolors. That is, the nozzles indicated by the solid lines aresubstantially arranged at a pitch of 300 μm in the Y direction. Sincethe nozzles of each of the ink-jet heads 120 a, 120 b, and 120 c arearranged at 70.5-μm intervals, every five nozzles of the nozzlesindicated by the broken lines are also arranged at a pitch of 300 μm inthe Y direction.

The process of manufacturing a color filter having an effective displayarea like the one shown in FIG. 10, i.e., coloring pixels of therespective colors like those shown in FIG. 9, by using the ink-jet headIJH having the nozzles 108 arranged in the above manner will bedescribed next. As described above, the ink-jet head IJH is positionedat an angle of 31.672° with respect to the glass substrate 1. As shownin FIG. 19, the respective ink-jet heads are shifted from each other by100 μm in the Y direction such that every five nozzles of each ink-jethead IJH are positioned above corresponding pixels. In this case, theink-jet heads 120 a, 120 b, an 120 c have the same structure regardlessof the colors of inks. In the actual manufacturing apparatus, theink-jet heads are fixed, and a glass substrate is moved. However, FIG.18 shows a state wherein the glass substrate is fixed, and the ink-jetheads are moved. Since the ink-jet heads and the glass substraterelatively move, it makes no difference whether the glass substrate isfixed or moved.

As shown in FIG. 18, the width of a portion at which each head can colorby one scanning operation corresponds to 102 pixels, which correspond to⅕ the 512 nozzles. The distance between the centers of the pixels on thetwo ends is 30.3 mm. That is, the entire effective display area of theglass substrate cannot be colored by one scanning operation in the Xdirection. For this reason, as shown in FIG. 18, after the ink-jet headIJH is scanned on the glass substrate once in the X direction, theink-jet head is relatively moved by 30.6 mm in the Y direction, and isscanned again in the X direction. This operation is repeated once tocolor the entire effective display area of the glass substrate.Meanwhile, each of the ink-jet heads 120 a, 120 b, and 120 c iscontrolled such that only every five nozzles are always used.

At this time, as shown in FIG. 20, with regard to one pixel, a pluralityof inks are continuously discharged from the same nozzle to cover theentire area of a frame of the black matrix 2 such that the center ofeach ink falls within the frame.

In a pre-discharging operation in step S10 in FIG. 17, which isperformed before coloring of one glass substrate is started, the ink-jethead IJH is normally controlled to cause only the nozzles used for acoloring operation to perform a pre-discharging operation. In thisembodiment, since a pressuring/restoring operation of discharging theink from all the nozzles is performed every time 30 glass substrates arecolored, the nozzles which are not used for a coloring operation are notused at all during such coloring operations. If a nozzle is not used fora certain period of time, an ink may solidify and clog up the nozzle. Inthis case, the nozzle may not be restored by a pressuring/restoringoperation. For this reason, in this embodiment, all the nozzles arecaused to perform a pre-discharging operation every time 10 substratesare colored.

With this operation, a pressuring/restoring operation which consumes anink can be performed at longer intervals. In addition, since only thenozzles to be used are caused to perform a discharging operation in anormal operation, the amount of ink consumed in restoring operations canbe minimized. Furthermore, by decreasing the number of times apressuring/restoring operation is performed, the number of substratescolored per unit time can be increased. By making use of the nozzleswhich are not used for coloring operations in this manner, even if theservice lives of every five nozzles used for coloring operations expire,this ink-jet head can be used again by arranging the remaining nozzlesto allow them to be used for coloring operations.

Second Embodiment

FIGS. 21 and 22 are views each showing the nozzle arrangement of anink-jet head IJH in a color filter manufacturing apparatus according tothe second embodiment of the present invention.

FIG. 21 shows the nozzle arrangement constituted by two arrays ofnozzles. The nozzles are arranged at a pitch of 70.5 μm, i.e., aresolution of 360 dpi, in the longitudinal direction of the head.

When this head is used for coloring of a color filter having pixels ofeach color arranged at a pitch of 300 μm as in FIG. 9, every six nozzlesindicated by the thick solid lines are used, and the head is tilted at44.829°.

FIG. 22 shows the nozzle arrangement constituted by three arrays ofnozzles. The nozzles are arranged at a pitch of 70.5 μm, i.e., aresolution of 360 dpi, in the longitudinal direction of the head.

When this head is used for coloring of a color filter having pixels ofeach color arranged at a pitch of 300 μm as in FIG. 9, every six nozzlesindicated by the thick solid lines are used, and the head is tilted at44.829°, as in the case shown in FIG. 21.

With the ink-jet heads having the above nozzle arrangements as well, thesame effects as described above can be obtained by performing dischargecontrol in the same manner as in the above embodiment.

Third Embodiment

A color filter manufacturing apparatus of the third embodiment has thesame arrangement as that of the first embodiment. The third embodimentis characterized by its control method. For this reason, a descriptionof the apparatus will be omitted, and the third embodiment will bedescribed with reference to the drawings used to described the firstembodiment.

As shown in FIG. 18, the width of a portion which each head can color byone scanning operation corresponds to 102 pixels, which correspond to ⅕the 512 nozzles. The distance between the centers of the pixels on thetwo ends is 30.3 mm. That is, the entire effective display area of theglass substrate cannot be colored by one scanning operation in the Xdirection. For this reason, as shown in FIG. 18, after an ink-jet headIJH is scanned on the glass substrate once in the X direction, theink-jet head is relatively moved by 30.6 mm in the Y direction toposition the nozzles used for the previous scanning operation above thecorresponding pixels so as to discharge the ink from the same nozzles asthose used in the previous scanning operation. Meanwhile, the ink-jethead is scanned again in the X direction. As shown in FIG. 18, after thesecond scanning operation, a 28-pixel portion of each color is leftuncolored. The ink-jet head IJH is therefore relatively moved in the Ydirection to position the nozzles used in the previous scanningoperation above the corresponding pixels, and each head is scanned againin the X direction to color the entire effective display area of theglass substrate by using 28 nozzles of the nozzles used in the previousscanning operation. An X-Y stage 22 is moved to move each head in the Ydirection immediately after coloring of the last pixel in one scanningoperation so as to change the position of each head relative to theglass substrate between scanning operations. Meanwhile, each of ink-jetheads 120 a, 120 b, and 120 c is controlled to always use only everyfive nozzles.

At this time, as shown in FIG. 20, with regard to one pixel, a pluralityof inks are continuously discharged from the same nozzle to cover theentire area of a frame of the black matrix 2 such that the center ofeach ink falls within the frame.

As described above, the nozzles which are not used in the previousscanning operation are not used in the succeeding scanning operation,but the nozzles which are used in the previous scanning operation arealways used in the succeeding scanning operation. For this reason, allthe nozzles used for a coloring operation are in an idle state for onlya short period of time, and hence each head is kept in a state in whichit can stably discharge an ink. Therefore, a high-quality coloringoperation can always be performed. In addition, since the heads need notbe relatively moved to the positions of the caps or portions forreceiving pre-discharged inks so as to perform a pre-dischargingoperation, the coloring time per substrate can be shortened, and theproduction per unit time increases, realizing a reduction in the cost ofa color filter.

With the ink-jet heads having the above nozzle arrangements shown inFIGS. 21 and 22 as well, the same effects as described above can beobtained by performing discharge control in the same manner as in thisembodiment.

In this embodiment, a coloring operation is performed by using themaximum number of nozzles which can be used in the first to sixthscanning operations, and using only about ¼ the nozzles in the remainingscanning operations. However, the same effects as described above can beobtained by using any combination of the numbers of nozzles to be usedas long as the nozzles which are used in the previous scanning operationare always used in the succeeding scanning operation, and the number ofnozzles used is decreased.

Fourth Embodiment

A color filter manufacturing apparatus of the fourth embodiment is thesame as that of the first embodiment except for the numbers of heads andnozzles. Only the differences between the fourth and first embodimentswill be described below.

As shown in FIG. 23, the maximum width of a portion at which each headcan color by one scanning operation corresponds to 272 pixels, whichcorrespond to ⅕ the 1,360 nozzles. The distance between the centers ofthe pixels on the two ends is 81.6 mm. That is, the entire effectivedisplay area of the glass substrate cannot be colored by one scanningoperation in the X direction. For this reason, as shown in FIG. 23,after an ink-jet head IJH is scanned on the glass substrate once in theX direction (scan 1), the ink-jet head is relatively moved by 81.6 mm inthe Y direction (step 1) to position the nozzles used for the previousscanning operation above the corresponding pixels so as to discharge theink from the same nozzles as those used in the previous scanningoperation. Meanwhile, the ink-jet head is scanned again in the Xdirection (scan 2). As shown in FIG. 23, after the second scanningoperation (scan 2), 96-pixel portion of each color is left uncolored.The ink-jet head IJH is therefore relatively moved in the Y direction(step 2) to position the nozzles used in the previous scanning operation(scan 2) above the corresponding pixels, and each head is scanned againin the X direction (scan 3) to color the entire effective display areaof the glass substrate by using 96 nozzles of the nozzles used in theprevious scanning operation (scan 2). An X-Y stage 22 is moved to moveeach head in the Y direction immediately after coloring of the lastpixel in one scanning operation so as to change the position of eachhead relative to the glass substrate between scanning operations.

Meanwhile, each ink-jet head IJH is controlled to always use only everyfive nozzles.

Consider a nozzle 200 on the left end of an ink-jet head 120 a in thecase shown in FIG. 23. A thick solid line 201 indicates the distance thenozzle 200 has moved without discharging any ink between the firstscanning operation (scan 1) and the second scanning operation (scan 2).The length of this thick solid line can be calculated as follows,provided that the distance between the heads on the two ends in thescanning direction is 48 mm:(95.598×sin 31.672°+48)×2+81.6=277.989 (mm)

The case shown in FIG. 24 in the fourth embodiment of the presentinvention will be described next.

In the case shown in FIG. 24, the numbers of nozzles used in therespective scanning operations (including the last scanning operation)are set to be almost the same. That is, all the nozzles are divided intogroups including almost the same number of nozzles such that 214 nozzlesare used for the first scanning operation (scan 1); 213 nozzles, for thesecond scanning operation (scan 2); and 213 nozzles, for the thirdscanning operation (scan 3). Consider a nozzle 202 (to be used todischarge an ink) on the left end of the ink-jet head 120 a, as in thecase shown in FIG. 23. A thick solid line 203 indicates the distance thenozzle 202 has moved without discharging any ink between the firstscanning operation (scan 1) and the second scanning operation (scan 2).The length of this thick solid line can be calculated as follows,provided that the distance between the heads on the two ends in thescanning direction is 48 mm as in the case shown in FIG. 23:(75.153×sin 31.672°+48)×2+64.2=239.119 (mm)

As is apparent from this calculation, the distance each ink dischargingnozzle moves without discharging any ink between scanning operations inthe case shown in FIG. 24 is shorter than that in the case shown in FIG.23. This means that the time during which each nozzle discharges no inkis shortened. If an ink in a given nozzle is kept in contact with airwithout being discharged, volatile components in the ink evaporate toincrease the viscosity of the ink. As a result, a discharge failure,i.e., inability to discharge the ink, or twisting, i.e., inability todischarge the ink straight, may occur. In order to prevent such aphenomenon, it is important to minimize the time during which the inkdischarging nozzle is caused to stand without discharging any ink.

Since the time during which the ink discharging nozzle is in contactwith air between scanning operations is shorter than that in the caseshown in FIG. 23, a discharge failure and twisting occur lessfrequently. That is, there is provided a color filter manufacturingapparatus which stabilizes the discharging operation of each ink-jethead, and suppresses the occurrence of defective products, therebyattaining an increase in yield.

With the ink-jet heads having the above nozzle arrangements shown inFIGS. 21 and 22 as well, the same effects as described above can beobtained by performing discharge control in the same manner as in thisembodiment.

In each of the cases shown in FIGS. 23 and 24, one screen is colored byperforming a scanning operation three times. However, the presentinvention is not limited to this. A scanning operation may be performedfour or more times. This embodiment is especially effective for a casewherein an area which can be colored by one scanning operation isslightly less than a fraction of an integer of one screen, and onescreen is colored by three or more scanning operations.

Fifth Embodiment

Each ink-jet head used in the fifth embodiment has nozzles arranged at apitch of 70.5 μm. The nozzle array is tilted in a scanning direction,and for example, every six nozzles are used to color pixels of the samecolor. A color filter manufactured by the apparatus of this embodimenthas the same color pattern as that shown in FIG. 9.

FIG. 25 shows the arrangement of the color filter manufacturingapparatus of the fifth embodiment. Reference numeral 301 denotes adrawing image (the pixel array pattern of a color filter) which is dataindicating the relative position relationship between ink dots to beformed on a substrate 1; and 302, a nozzle switching signal fordesignating a switching operation for nozzles corresponding to therespective pixels of the color filter. A nozzle group switching methodwill be described in detail with reference to FIGS. 25 and 1. Assumethat the second, seventh, and twelfth nozzle groups, counted from theright end, are being used. In this case, sequential use of nozzle groupsis easy to perform. That is, the third, eighth, and thirteenth nozzlegroups are used for the next operation, and the fourth, ninth, andfourteenth nozzle groups for the still next operation. However, anotherswitching method may be used. In addition, a nozzle group switchingoperation is performed when the service lives of the currently usednozzles expire. For example, the service life of each nozzle is based onthe operating time of one nozzle group. When the operating time of onenozzle group reaches a predetermined time, it is determined that theservice life has expired. Reference numeral 303 denotes a drawing datagenerator for generating drawing data as data indicating the absoluteposition of each ink dot on a substrate by relating each pixel on thesubstrate with a corresponding nozzle in accordance with a nozzleswitching signal. In this case, upon switching of nozzles, a change inthe position of each nozzle after the nozzle switching operation iscalculated from known data associated with a nozzle arrangement, and theposition of a stage 308 is changed in accordance with the calculatedchange in forming each ink dot before and after the nozzle switchingoperation. Reference numeral 304 denotes a driver for driving an ink-jethead 305 and feeders 306 and 307 in accordance with the drawing data toform ink dots corresponding to the drawing data on the substrate 1. Theink-jet head 305 includes a red head 305 a for discharging a red ink, agreen head 305 b for discharging a green ink, and a blue head 305 c fordischarging a blue ink. The feeders 306 and 307 respectively move theposition of the stage 308 in the X and Y directions in accordance with asignal from the driver 304. The stage 308 holds the substrate 1 to becolored. With the above arrangement, a drawing pattern 310 correspondingto the drawing image 301 is formed on the substrate 1.

In this embodiment, a change in the positional relationship between asubstrate and each drawing head, which occurs upon nozzle switching andcorresponds to an offset amount of each nozzle position, is estimatedfrom known data associated with a nozzle arrangement. However, thepositional relationship between ink dots actually formed by therespective nozzles may be measured by using an image processingapparatus.

In many actual configurations, the nozzle switching signal 302 and thedrawing data generator 303 are realized as the function of one or aplurality of computers connected to each other.

In this embodiment, the means for switching nozzle groups to be usedcorresponds to the nozzle switching signal 302 and the drawing datagenerator 303, the means for estimating or measuring a change in thepositional relationship between the substrate 1 (pixel) and each nozzleof each ink-jet head, which corresponds to an offset amount of eachnozzle, corresponds to the drawing data generator 303, and the means forchanging the positional relationship between the substrate 1 and eachink-jet head (nozzle) corresponds to the drawing data generator 303, thedriver 304, and the feeders 306 and 307.

Sixth Embodiment

FIG. 26 shows the arrangement of a color filter manufacturing apparatusof the sixth embodiment. In the fifth embodiment, detection of adefective nozzle and nozzle switching are externally performed. Incontrast to this, in this embodiment, a discharge count calculator 311is used to calculate the number of times each nozzle discharges an inkon the basis of the operating time of the nozzle and the number of timesthe nozzle discharges the ink per unit time, thereby estimating adefective nozzle and performing nozzle switching.

In this embodiment, a defective nozzle is estimated by calculating thenumber of times each nozzle discharges an ink on the basis of theoperating time of the nozzle and the number of times the nozzledischarges the ink per unit time. However, the number of times eachnozzle discharges an ink may be directly measured, or an imageprocessing apparatus or the like may be used to detect a defectivenozzle on the basis of the state of each ink dot.

In this embodiment, since nozzle switching is automatically performed,labor saving can be easily realized, and a continuous operation can beperformed for a long period of time, as compared with the fifthembodiment.

Seventh Embodiment

FIG. 27 shows the arrangement of a color filter manufacturing apparatusof the seventh embodiment. In this embodiment, the temperaturedistribution of each nozzle of each ink-jet head is measured, and nozzleswitching is performed in accordance with the measurement result.

In the color filter manufacturing apparatus, the layouts of ink dotsdrawn in coloring operations are identical to each other, and a changein the temperature of each nozzle in use exhibits almost a constantpattern. In addition, temperature environments such as externaltemperatures are almost constant in many instances. For this reason, thetemperature of each nozzle can be estimated from the operating time ofthe nozzle. In this embodiment, the temperature of each nozzle isactually measured to perform nozzle switching. However, almost the sameeffect can be obtained by using a method of performing nozzle switchingat predetermined intervals without actually measuring the temperature ofeach nozzle.

In the above embodiments, since a rise in the temperature of each nozzleis suppressed, a discharge failure due to scorching of an ink or thelike can be prevented. In addition, since an idle time is set for eachnozzle after a predetermined operating time, the service life of thenozzle is prolonged.

In the above embodiments, the black matrix 2 is formed on the substrate1. However, the present invention is not limited to this. For example,in FIGS. 3A to 3F, the black matrix 2 may be formed on the othersubstrate which opposes the glass substrate 1. In this case, an ink isdischarged into the frame of each portion 5 having no affinity for anink in FIG. 2D.

In the above embodiments, as each ink-jet head, a bubble-jet typeink-jet head is used, in which an ink on the heater 102 is boiled toproduce a bubble, and the ink is pushed and discharged from thedischarging opening 108 upon volume expansion of the bubble. However,the present invention is not limited to this. For example, an ink-jethead using a piezoelectric element may be used.

According to the above description, the present invention is applied tothe print apparatus of the system, among various ink-jet recordingsystems, which has a means (e.g., an electrothermal converter or laserlight) for generating heat energy as energy used to discharge an ink,and changes the state of an ink by using the heat energy. According tothis system, a high-density, high-definition recording operation can berealized.

As for the typical structure and principle, it is preferable that thebasic structure disclosed in, for example, U.S. Pat. No. 4,723,129 orU.S. Pat. No. 4,740,796 is employed. The above method can be adapted toboth a so-called on-demand type apparatus and a continuous typeapparatus. In particular, a satisfactory effect can be obtained when theon-demand type apparatus is employed because of the structure arrangedin such a manner that one or more drive signals, which rapidly raise thetemperature of an electrothermal converter disposed to face a sheet or afluid passage which holds the fluid (ink) to a level higher than levelsat which film boiling takes place are applied to the electrothermalconverter in accordance with recording information so as to generateheat energy in the electrothermal converter and to cause the heateffecting surface of the recording head to take place film boiling sothat bubbles can be formed in the fluid (ink) to correspond to the oneor more drive signals. The enlargement/contraction of the bubble willcause the fluid (ink) to be discharged through a discharging opening sothat one or more inks are formed. If a pulse shape drive signal isemployed, the bubble can be enlarged/contracted immediately andproperly, causing a further preferred effect to be obtained because thefluid (ink) can be discharged while revealing excellent responsibility.

It is preferable that a pulse drive signal disclosed in U.S. Pat. No.4,463,359 or U.S. Pat. No. 4,345,262 is employed. If conditionsdisclosed in U.S. Pat. No. 4,313,124 which is an invention relating tothe temperature rising ratio at the heat effecting surface are employed,a satisfactory recording result can be obtained.

As an alternative to the structure (linear fluid passage orperpendicular fluid passage) of the recording head disclosed in each ofthe above inventions and having an arrangement that discharge ports,fluid passages and electrothermal converters are combined, a structurehaving an arrangement that the heat effecting surface is disposed in abent region and disclosed in U.S. Pat. No. 4,558,333 or U.S. Pat. No.4,459,600 may be employed. In addition, the following structures may beemployed: a structure having an arrangement that a common slit is formedto serve as a discharge section of a plurality of electrothermalconverters and disclosed in Japanese Patent Laid-Open No. 59-123670; anda structure disclosed in Japanese Patent Laid-Open No. 59-138461 inwhich an opening for absorbing pressure waves of heat energy is disposedto correspond to the discharge section.

Furthermore, as a recording head of the full line type having a lengthcorresponding to the maximum width of a recording medium which can berecorded by the recording apparatus, either the construction whichsatisfies its length by a combination of a plurality of recording headsas disclosed in the above specifications or the construction as a singlefull line type recording head which has integrally been formed can beused.

In addition, the invention is effective for a recording head of thefreely exchangeable chip type which enables electrical connection to therecording apparatus main body or supply of ink from the main device bybeing mounted onto the apparatus main body, or for the case by use of arecording head of the cartridge type provided integrally on therecording head itself.

It is preferred to additionally employ the recording head restoringmeans and the auxiliary means provided as the component of the presentinvention because the effect of the present invention can be furtherstabled. Specifically, it is preferable to employ a recording headcapping means, a cleaning means, a pressurizing or suction means, anelectrothermal converter, an another heating element or a sub-heatingmeans constituted by combining them and a sub-emitting mode in which anemitting is performed independently from the recording emitting in orderto stably perform the recording operation.

Although a fluid ink is employed in the above embodiments of the presentinvention, an ink which is solidified at the room temperature or lower,or an ink which is softened or liquified at the room temperature may beused. That is, any ink which is liquified when a recording signal issupplied may be used.

Furthermore, an ink which is solidified when it is caused to stand, andliquified when heat energy is supplied in accordance with a recordingsignal can be adapted to the present invention to positively prevent atemperature rise caused by heat energy by utilizing the temperature riseas energy of state transition from the solid state to the liquid stateor to prevent ink evaporation. In any case, an ink which is liquifiedwhen heat energy is supplied in accordance with a recording signal so asto be discharged in the form of fluid ink, or an ink which is liquifiedonly after heat energy is supplied, e.g., an ink which starts tosolidify when it reaches a recording medium, can be adapted to thepresent invention. In the above case, the ink may be of a type which isheld as fluid or solid material in a recess of a porous sheet or athrough hole at a position to face the electrothermal converter asdisclosed in Japanese Patent Laid-Open No. 54-56847 or Japanese PatentLaid-Open No. 60-71260. It is the most preferred way for the ink to beadapted to the above film boiling method.

As has been described above, according to the present invention, sincean ink-jet head used in a general printer or an ink-jet head having asimple modification is used as an ink-jet head used to manufacture acolor filter, a reduction in the cost of an ink-jet head can beattained. A reduction in the cost of a manufacturing apparatus cantherefore be attained. In addition, the manufacturing cost per colorfilter can be reduced.

Since the amount of each ink used per color filter can be reduced, amore inexpensive color filter, a display device using the color filter,and an apparatus using the display device can be provided.

When one glass substrate is to be colored by performing a plurality ofscanning operations, the discharging operation of each ink-jet head canbe stabilized, and the occurrence of defective products can besuppressed. In addition, the color time required for one glass substratecan be shortened to increase the production per unit time. Therefore, acolor filter manufacturing method and apparatus which can manufacture acolor filter at a lower cost can be provided.

There is provided a color filter manufacturing apparatus which canstabilize the discharging operations of ink-jet heads, each havingdischarging nozzles arranged at a pitch matching with a pixel pitch, andsuppress the occurrence of defective products to attain an increase inyield by shortening the idle time between scanning operations, duringwhich each discharging nozzle of each ink-jet head discharges no ink,when the ink-jet heads are to be relatively scanned a plurality ofnumbers of times to color one substrate.

In addition, in each ink-jet head, nozzles to be used can be switched.Even if a failure occurs in a nozzle in use, the manufacture of a colorfilter can be continued by using another nozzle.

Furthermore, since the service life of each ink-jet head is prolonged ascompared with a conventional ink-jet head used for a color filter, thefrequency in replacing ink-jet heads decreases.

Moreover, the size and color density of each ink dot can be keptconstant. According to the present invention, since a rise in thetemperature of each nozzle is suppressed, a discharge failure due toscorching of an ink or the like can be prevented. In addition, since anidle time is set for each nozzle after a predetermined operating time,the service life of the nozzle is prolonged.

The present invention is not limited to the above embodiments andvarious changes and modifications can be made within the spirit andscope of the present invention. Therefore, to apprise the public of thescope of the present invention the following claims are made.

1-58. (canceled)
 59. A method of manufacturing a color filter having aplurality of colored pixels on a substrate by discharging an ink from anink-jet head having a plurality of ink discharging nozzles whileperforming relative movement of said ink-jet head and the substrate,comprising the steps of: dividing the plurality of ink dischargingnozzles for discharging an ink having a same color into a plurality ofnozzle groups; coloring the pixels of one substrate by using only onenozzle group in the plurality of nozzle groups for the same color; andswitching from the one nozzle group to an other nozzle group as a nozzlegroup to be used for the same color, wherein an operation of theswitching in said switching steps is not performed during coloring theone substrate.
 60. A method according to claim 59, further comprisingthe step of: adjusting relative positions of the pixels of the substrateand the nozzles of the other nozzle group selected by the switchingoperation.
 61. A method of manufacturing a liquid crystal panel having acolor filter, comprising the steps of: preparing the color filterproduced by the method of claim 1; and sealing a liquid crystal compoundbetween the color filter and a counter substrate.
 62. A method ofmanufacturing a color filter having a plurality of colored pixels on asubstrate, comprising the steps of: performing relative movement of thesubstrate and ink-jet heads corresponding to different colors, each ofthe ink-jet heads having a plurality of nozzle groups corresponding to asame color, each of the nozzle groups comprising a plurality of inkdischarging nozzles; forming the colored pixels having different colorsby discharging different color inks from respective nozzle groups forrespective different colors onto the pixels of the substrate whileperforming relative movement of the substrate and said inkjet heads aplurality of times; and switching, for respective different colors, fromthe one nozzle group to an other nozzle group as a nozzle group to beused, wherein, in coloring one substrate by plural relative movements insaid forming step, inks having different colors are discharged by usingonly one nozzle group of respective nozzle groups for respectivedifferent colors in the plural relative movements, and wherein anoperation of the switching in said switching step is not performedduring coloring of the one substrate.
 63. A method according to claim62, further comprising the step of: adjusting, for respective differentcolors, relative positions of the pixels of the substrate and thenozzles of an other nozzle group.
 64. A method of manufacturing a liquidcrystal panel having a color filter, comprising: preparing the colorfilter produced by the method of claim 62; and sealing a liquid crystalcompound between the color filter and a counter substrate.
 65. A methodof manufacturing a color filter having a plurality of colored pixels ona substrate by discharging an ink from an ink-jet head having aplurality of ink discharging nozzles while performing relative movementof the ink-jet head and the substrate, comprising the steps of: dividingthe plurality of ink discharging nozzles for discharging an ink having asame color into a plurality of nozzle groups, the plurality of nozzlegroups including at least a first nozzle group and a second nozzlegroup; coloring the pixels of one substrate by using only the firstnozzle group for the same color; switching from the first nozzle groupto the second nozzle group as a nozzle group to be used for coloring thepixels; adjusting relative positions of the pixels of the substrate andthe nozzles of the second nozzle group; and coloring the pixels of another substrate by using only the second nozzle group for the samecolor, wherein an operation of the switching in said switching step isnot performed during coloring of the substrate.
 66. A method accordingto claim 65, wherein the first nozzle group corresponds to positions ofthe pixels of the one substrate, and the second nozzle group does notcorrespond to the positions of the pixels of the one substrate, and thesecond nozzle group corresponds to a positions of the pixels of theother substrate and the second nozzle group does not correspond to thepositions of the pixels of the other substrate.
 67. A method accordingto claim 65, wherein the nozzles of the first nozzle group consist ofevery predetermined number of nozzles and the nozzles of the secondnozzle group consist of every predetermined number of nozzles, and eachof the nozzles of the second nozzle group are arranged between thenozzles of the first nozzle group respectively.
 68. A method ofmanufacturing a liquid crystal panel having a color filter, comprisingthe steps of: preparing the color filter produced by the method of claim7; and sealing a liquid crystal compound between the color filter and acounter substrate.